Both are used. After reading and writing these things a few times, I still don’t know which is preferable. But, sometimes the details bear on the choice. In the case of convert, it’s not unreasonable that a package would have a convert function that is semantically unrelated to Base.convert. In this case, writing Base.convert might reduce cognitive load a bit when reading the code.

Also, I can never remember how to use parens and quoting to write something like Base.==(x, y) ... Out of frustration, I often do import Base: ==.